The store had rules. This guy decided to break them. The store was within their right to ask him to leave. If they want to have an ethical policy relating to what food is sold in store, then all parties should abide by that. If he couldn't abide by the requirements of his landowner, then he should have left, rather than trying to circumvent rules he didn't intend to abide by.
The production of foie is extremely contentious and it's not something I would ever chose to eat, as I couldn't eat it knowing the suffering that animals have gone through to produce it.